I am uncut and I’ve been keeping my foreskin back and my glans exposed for years now. Before I started permanently retracting, my glans was indeed super sensitive, almost uncomfortably sensitive. It was uncomfortable for my glans to rub on underwear or sheets. And if I or a partner held my foreskin back and stimulated my glans directly, it was almost painfully sensitive. I couldn’t take it for long. I would pretty much only cum by rolling my foreskin back and forth over my glans.
Now that my glans has been exposed full time for so long, the sensitivity and sensations have changed. I don’t really notice rubbing on underwear. And I can touch and stimulate my glans directly however I want for as long as I want during sex and masturbation. It now feels just pleasurable, without any hint of pain or discomfort. And I wouldn’t describe my current sensation as desensitized; more like having the volume dial turned down from 11 to a very nice 7.